Long before “The Dark Knight” grossed more than the GDP of the Solomon Islands, director Christopher Nolan was known more for his dark explorations of the human psyche in his films “Memento” and “Insomnia” than for letting Christian Bale talk as if he swallowed a grizzly bear for 150 minutes.

Thus, it’s no surprise that the trailer for his upcoming film, “Inception,” declares: “Your Mind is the Scene of the Crime.” Set for a July 2010 release and starring Leonardo DiCaprio and Joseph Gordon-Levitt, “Inception” has Nolan, who also wrote the screenplay, returning to the concept of what’s real and what merely appears to be.

During production, details about the film's plot were closely guarded. The minute-long, dialogue-free trailer doesn't reveal much other than what seems to be the film’s four major themes--the city, gravity, water and DiCaprio looking confused. Gravity, or lack thereof, is the most interesting of the four. The opening shot of a top spinning and slowly falling is contrasted with the brief Matrix-like scene in which Gordon-Levitt runs along the walls of a hotel and jumps at DiCaprio, who is then thrown backwards as up becomes down, left becomes right, and away we go down the rabbit hole.

In part, the trailer’s surreal feeling is accomplished by the treatment of the city itself. Set to industrial music, the opening helicopter shot of a freeway snaking through downtown helps to build to the final reveal of the trailer--a massive zoom-out in which the city becomes a maze, one complicated enough to lend some credibility to DiCaprio’s puzzled and fearful facial expressions throughout.

Final judgment on whether “Inception” has the potential to be a success should be spared until a more complete trailer is released. That said, it is noteworthy that this is Nolan’s first completely original work since his film debut in 1998. His past five films all have been based on some sort of source material, be it a short story, a novel or most famously, a comic book. Already, the specter of “The Dark Knight” has proved difficult for Nolan to escape. Just a glance at the movie poster for “Inception" suggests something familiar about the protagonist’s pose--he's standing in front of a city in distress, completely surrounded by skyscrapers and looking, for all intents and purposes, ready to kick some serious butt.